Water soluble substituted aminomethylene mercapto acids and the process for their synthesis



Patented Dec. 23, 1941 WATER SOLUBLE SUBSTITUTED AMINO- METHYLENE MERCAPTO ACIDS AND THE PROCESS FOR THEIR SYNTHESIS Max Engelmann, Wilmington, DeL, Emeric Havas, Pitman, N. J., and Morris 8. Kharasch, Chicago, Ill., assignors to E. I. du Pont de Nemonrs 8: Company, Wilmington, Del., a corporation of Delaware 1% Drawing. Application April as, 1939, Serial No. 210,512

13 Claims.

This invention relates to the preparation of new water soluble organic compounds, and more particularly to the preparation of new water soluble dyes, and fiber treating agents from com-' pounds containing a free amine group that are ordinarily insoluble in water.

In the treatment of fibers such as in the dyeing of cellulose acetate and related fibers, in water proofing fabrics, and in the preparation of certain types of papers, the compounds with which the fibers are to be treated, are in many cases, water insoluble. These compounds have heretofore been employed as colloidal suspensions, or dissolved in organic solvents from which they precipitate in the fibers, for in most cases it has been impossible to convert them to water soluble compounds that could be reconverted to the required water insoluble form on the fiber.- Many of these compounds contain primary amine groups, and we have found that this class of compounds, namely those containing at least one primary amine group can be converted into water soluble compounds that are readily reconvertible to the original +water insoluble form on the fiber when it is desired.

It is therefore an object of this invention'to provide a process forconverting organic primary amino compounds, which are ordinarily water insoluble, to a water soluble derivative, from which they may be readily reconverted to the water insoluble form when it is desired.

It is a further object of the invention to prepare new water soluble fiber treating agents which can be rendered water insoluble in the fibers during or after their application.

It is a still further object of the invention to prepare water soluble dyes for cellulose acetate and related fibers, from those compounds that have heretofore been applied to such fiber as colloidal suspensions.

We have found that those dyestufi's and other organic compounds which are normally water insoluble but which carry a primary amine group can be rendered water soluble when they are treated with formaldehyde and a compound of the type HS-R, in which R stands for an organic radical which carries an acidic solubilizing group, and that these compounds are capable of being reconverted to the parent substance,

- on heating, making it possible to apply them to the fibers in true solution form, as distinguished from the suspensions heretofore employed, yet permitting them to be fixed in the fiber in the water insoluble form when it is desired.

plicable to the preparation of cellulose acetate dyes, and in the coloring and treatment of paper stock where compounds which contain free amine groups are frequently employed asv colloidal suspensions.

According to the present invention, the primary amine compound is reacted with the formaldehyde and a mercapto organic acid at room temperature or higher temperatures with or without the use of a solvent. The resulting compounds carry the radical in which R stands for the organic radical of a mercapto acid, and A for the acid radical in the for of the free acid or alkali metal salt.

Where the reaction medium is alkaline, the wagroup is already present in the aliphatic chain,

it must be on the carbon atom to which the amine group is attached, such as in those com-= pounds formed by the reaction of formaldehyde on the amine prior to the addition of the mercapto acid.

The following examples are given to illustrate the invention. The parts used are by weight.

, Example 1 20 parts of l-aminoanthraquinone, 160 parts I of alcohol 96%, 15 parts thioglycolic acid and 15 parts of formaldehyde 37%, are refluxed together for one hour. The mass is then diluted with 600 parts of water, filtered, and the resulting cake is dissolved in 1000 parts of water and 15 parts of soda ash. The red solution is filtered from impurities and salted with parts of common salt. After standing for some time the product is filtered oil. and dried. It is easily soluble in water and dyes cellulose acetate silk without the addition of any dyeing assistant in yellowish orange shades.

Example 2 This method of solubilizing is particularly ap- 60 parts 1,4-diaminoanthraquinone, parts of alcohol 96%, 40' parts of thioglycolic acid, 40 parts of formaldehyde when reacted and worked up by the same procedure described in Example 1 gives a product which dissolves in water with a blue color and dyes cellulose acetate silkflin red violet shades.

Example 3 20 parts of 1,4,5,8-tetraminoanthraquinone, 160 parts of alcohol 96%, 40 parts thioglycolic acid and 40 parts formaldehyde (37%) are refluxed for one hour, diluted with 600 parts of water. filtered, dissolved in 600 parts of water and 20 parts of soda ash, and the solution evaporated to dryness. The product is soluble in water with blue color and dyes cellulose acetate silk in blue shades. This product, according to sulfur and nitrogen analysis contains the solubilizing Example 4 12 parts of thioglycolic acid are diluted with 200 parts of water, neutralized with '7 parts of soda ash until weakly alkaline to brilliant yellow paper. 10 parts of formaldehyde (37%) and 10 parts of 1,4,5,8-tetraminoanthraquinone are then added. The mixture is warmed to from 55 to 60 C., with constant stirring, until the tetramine is dissolved, which generally takes place in about fifteen minutes. The solution is evaporated to dryness. The product obtained has the same properties as the product of Example 3. In a similar manner soluble cellulose acetate dyes can be obtained by starting with Z-aminoanthraquinone, 5-nitro-1,4-diaminoanthraquinone, 1- amino-i-hydroxy anthraquinone, 1 amino 4- methylaminoanthraquinone, 1-amino-5-nitroanthraquinone, 4,8-diaminoanthrarufin, aminobenzanthrone, 1-amino-4-anilinoanthraquinone, l-methylamino-i-(y-amino anilino) -anthraquinone, etc., all of which dye cellulose acetate when solubilized, in the same shades as the parent compound.

Eatample 5 parts of 1,4-diaminoanthraquinone, 10 parts of glacial acetic acid, 100 parts of water, 5 parts of paraformaldehyde, and 10 parts of thioglycolic acid are heated together to the boil for one hour. On cooling a crystalline body separates, which is filtered and washed with water. This product is heated with sodium carbonate in water solution and the insoluble impurities are removed by filtration. The solution is salted with common salt and the precipitate filtered off. It is soluble in water and dyes cellulose acetate in reddish violet shades.

, Example 6 10 parts of 1,4,5,8-tetraminoanthraquinone, 10 parts of glacial acetic acid, 100 parts of water, 20 parts of thioglycolic acid and 10 parts of paraformaldehyde are heated together at 80 to 100 C. for one hour. The product is isolated as outlined in Example 5. It dyes cellulose acetate in brilliant blue shades.

Example 7 19.7 parts of amino-azo benzene are dissolved in parts of thioglycolic acid and 7.5 parts of formaldehyde (as 40% aqueous solution) added. After gentle warming, the reaction is complete, the reaction mass is drowned in water and the free acid is isolated. On conversion to the sodium salt with sodium carbonate a greenish yellow product is obtained which is soluble in water. It dyes cellulose acetate from a. slightly alkaline bath a heavy shade of yellow. The dye appears to be on the fiber as the free base since it can be diazotized and developed with beta-hydroxy-naphthoic-acid.

Example 8 In place of amino-azo benzene in Example 5, 13.6 parts of the dye prepared by coupling pnitro-aniline diazo with N-(beta-amino-ethyD- meta-toluidine are used. The red product obtained (after conversion to the sodium salt) is soluble in water and dyes cellulose acetate from an alkaline bath a reddish orange shade. The product is believed to have the formula:

oar-ON: QNHCHzCHzNHCHzSCHzCOONa Example 9 112.5 parts of formaldehyde (as a 40% solution) are added to parts of 85% thioglycolic acid. The resulting solution is added to a hot suspension of 242 parts of the dye, 4-amino-4- nitro-azo-benzene, suspended in 2500 parts of ethyl alcohol. The reaction is rapid and the dye dissolves completely. The solution is cooled and drowned in water and the resulting free acid is filtered and converted to the sodium salt. The dark red powder obtained is readily soluble in cold water giving an orange solution. The product dyes cellulose acetate a strong orange shade. It has the following probable formula:

oar-O rs: ONHCHzS-CHzCOONa The thioglycolic acid-formaldehyde addition compounds of the following products may be prepared by procedures similar to Examples 5, 6 and 7:

4-amino-4'-dimethyl-amino-azo-benzene 4-amino-4-(ethyl-, hydroxy-ethyl amino) azobenzene 4-amino-4'-[di-(hydroxy ethyl) amino] azobenzene 4-amino-2,5-dimethyl-4'-nitro-azo-benzene Example 10 It is easily soluble in diluted sodium hydroxide, carbonate or ammonia solutions, and is reconverted to the insoluble stearamide by treating the solution with dilute acid or with heat.

Example 11 l 7 parts of para-nitraniline are stirred with 10 parts of thioglycolic acid and 4 parts of 40% formaldehyde solution are added. The condensation product is formed immediately. After the addition of 100 parts of water, the product is isolated by filtration. It is easily soluble in diluted sodium carbonate or ammonia solution and melts at 156-l58 C.

A similarly water soluble compound may beob- 1 tained by employing beta-sulioethylmercaptan in 5% to sulfuric acid solution in place of the thioglycolic acid in this example.

Example 12 20 'parts of 1-amino-5-ethoxy-benzo-thiazole are slurried with 150 parts of 96% alcohol;

' solution. According to the nitrogen and sulfur analysis it has the following formula:

\ o-nn-cm-a-cmooori Example 13 40 parts of acridine yellow base (Color Index #785), and 40 parts of thioglycolic acid are dissolved in 2000 parts of water and 80 parts of 40%. formaldehyde solution are added. After standing for twelve hours, the condensation product crystallizes out and is recovered by filtration. It is easily soluble in diluted alkaline media as for example sodium hydroxide, carbonate or ammoma.

Example 14 81 parts of 2,4-dichloro-aniline are dissolved in 80 parts of alcohol. To this solution there is added 18 parts of formaldehyde (in the form of formalin solution) and 92.4 parts of thiosalicylic acid. The mixture is gently warmed. It is then neutralized with sodium carbonate solution and diluted with water, giving a clear solution.

By substituting molecular equivalents of thioglycolic acid for the thiosalicylic acid employed in thisexample a similar water soluble product is obtained.

Example 15 isolated by evaporation as disclosed in the above examples. Methyl alcohol or acetone may be substituted for the dioxane in this example.

Example 1 6 127 parts of N-heptadecylamine are suspended in 80 parts of alcohol. To this suspension, 92.4 parts of thiosalicylic acid and 15 parts of formaldehyde (40% solution) are added. The mixture is warmed until complete solution results. It is then neutralized with sodium carbonate, giving a water soluble product.

Example 1 7 69 parts of para-nitroaniline are dissolved in 80 parts of alcohol. Into this solution there is added 15 parts of formaldehyde (40% solution) and 114 parts of para-sulfhydryl phenyl-sulfonic acid. The mixture is warmed until complete solution results. It is then neutralized'with sodium carbonate, giving a water soluble product which may be isolated by evaporation as above described.

The ease with whichthe. water soluble compounds which have been illustrated are re'con verted to the water insoluble parent products varies with the individual compounds. The compounds resulting from the use of the thiosalicylic and para-sulfhydryl phenyl-sulfonic acids are relatively unstable in strong alkalies and therefore sodium carbonate should be employed in the preparation of their sodium salts.

Other mercapto-carboxylic or mercapto-sulfonic acids may, of course, be employed in the above illustrated reactions to give water soluble products. The purity of the mercapto acids is, of course, an essential factor'in the formation of these new water soluble compounds in high yields. Where thioglycolic acid is employed, it should be of high purity. It is understood that mixed mercapto acids which result from the sulfonation of chlor-containing hydrocarbon fractions may, of course, be employed when converted to the corresponding mercaptan.

In the specification and claims, the term mercapto acid isused to designate those compounds of the formula HSR'A where R is an organic radical containing an acid solubilizing group A such as CO0H and SO3H, and their alkali metal salts.

We claim:

1. In the process for preparing water soluble compounds from water insoluble primary organic amines which when of the carbocyclic series are unsubstituted on at least One carbon atom ortho to the amino group, the step which comprises reacting the prlmary organic amine with formaldehyde and a mercapto acid of the class consisting of mercapto carboxylic and mercapto sulfonic acids.

2. In-the process for-preparing water soluble compounds from water insoluble primary organic amines which when of the carbocyclic series are unsubstituted on at least one carbon atom ortho to the amino group, the steps which comprise reacting the primary organic amine with formaldehyde and a mercapto acid of the class consisting of mercapto carboxylic and mercapto sulfonic acids and converting the resulting product to its alkali metal salt.

3. In the process for preparing water soluble organic compounds from water insoluble primary organic amines which when of'the carbocyclic series are unsubstituted on at least one carbon atom ortho to the amino group, the step which comprises reacting the organic amine with formaldehyde and thioglycolic acid.

4. In the process for preparing water soluble compounds from water insoluble primary organic amines which when of the carbocyclic series are unsubstituted on at least one carbon atom ortho to th amino group, the steps which comprise reacting the organic amine with formaldehyde, then. reacting the resulting compound with a mercapto acid of the class consisting of mercapto carboxylic and mercapto sulfonic acids.

5. A water soluble organic amine having the general formula R'(NHCH2S-RA)n in which R is the organic radical of an organic amine which organic amine without the substituent -CH2-SR,A is water insoluble, and in is water insoluble and in which -S-R-'A stands for an organic acid compound of the class consisting of organic mercapto carboxylic acids and organic mercapto sulfonic acids and their alkali metal salts which are connected to the methylene group through the mercapto radical and 1: stands for anumber from 1 to 4.

7. The water soluble amino anthraquinone compounds of the general formula Aq-.(NH-CH2S-RA) n in which Aq stands for an anthraquinone group which in the form of the free amine and without the substituent CH2S-Rr-A is water insoluble and in which S-RA stands for an organic acid compound of the class consisting of organic mercapto carboxylic acids and organic mercapto sulfonic acids and their alkali metal salts which are connected to the methylene group through ganic acid compound of the class consisting of organic mercapto carboxylic acids and organic mercapto sulionic acids and their alkali metal salts which areccnnected to the methylene group through the mercapto radical and It stands for a number from 1 to 4.

10. The water soluble organic amine having its general formula in which R stands for an organic radical of an I organic amine which organic amine without the substituent CH2-S-CH2-COOM is water insoluble and in which M stands for an element of the class consisting of hydrogen and the alkali metals and n for a number from 1 to 4.

11. The water soluble color bodies of the general formula in which Chromo stands for the radical of an organic compound which exhibits dyeing properties and which as the free amine and without the substituent CHz-SCH2-.COOM is water insoluble and in which M stands for an element of the class consisting of hydrogen and the alkali metals and n for a number from 1 to 4.

the mercapto radical and 1: stands for a number from 1 to 4.

8. The water soluble azo color bodies of the general formula Azo(NHCHz-SRr-A in which Azo stands for the radical of an azo dye molecule which in the form of the free amine and without the substituent CH2SRA is water insoluble and in which -SR--A stands for an organic acid compound of the class consisting of organic mercapto carboxylic acids and organic mercapto sulfonicracids and their alkali metal salts which are connected to the methylene group through the mercapto radical and n stands for a number from 1 to 4.

9. The water soluble aliphatic compounds of the general formula Y(NH-CH2S-RA)n in which Y stands for the organic radical of an aliphatic amine which aliphatic amine without the substituent CH-.-S-RA is water insoluble and in which --SR-A stands for an or- 12. The water soluble Azo color bodies'oi the general formula in which Azo stands for the radical of an azo dye molecule which in the form of the free amine and without the substituent is water insoluble and in which M stands for an element of the class consisting of hydrogen and the alkali metals and n for a number from 1 to 4.

13. Water soluble aliphatic compounds of the general formula in which Y stands for the organic radical of an aliphatic amine which aliphatic amine without the substituent CH2SCH2-COOM is water insoluble and in which M stands for an element of the class consisting of hydrogen and the alkali metals and n for a number from 1 m4.

MAXENGEIMANN. EMERIC HAVAS. MORRIS S. KHARASCH. 

